What Causes Severe Myelopathy Resulting in Acute Quadriplegia after a Surgery for Atlantoaxial Subluxation due to Os Odontoideum? A Case Report.

A case of acute quadriplegia resulting from reduction of atlantoaxial subluxation due to os odontoideum is rare. Patient with os odontoideum are at a greater risk for atlantoaxial instability and resultant spinal cord compression. In our case, the patient exhibited mild myelopathic symptoms before the onset of acute quadriplegia. Owing to the clinical presentations, the spinal cord not only seemed to suffer a mechanical compression but also an insufficiency of blood supply to the spinal artery and its branches. No other report has described the findings from magnetic resonance imaging before and after the onset of acute myelopathy after surgery. The aim of our case report is to highlight the pathophysiology and appropriate management strategy of a patient with severe progressive spinal cord myelopathy after surgery, secondary to chronic atlantoaxial subluxation due to os odontoideum. This case depicts the presence of this rare yet possible complication, and emphasizes the importance of preoperative evaluation in cases with chronic progressive myelopathy. Moreover, urgent postoperative treatment and rehabilitation are important for the recovery of neurological symptoms.